You cannot trap all signals - some are processed regardless of the the trap
shows the names and numbers of all of the signals you system uses. There are differences between unixes in what this display shows.
Suppose you want to trap control/c - SIGINT, signal =2 on my system.
You can use either the number 2 or the name - drop the "SIG" part and you can use INT
hi!!,
i wanna trap all Signal 10, 11, 15 generated by any process running on my server irrespective of the user and wanna write to a log file. Any ideas? Do this script need to be a root process??
:cool: (1 Reply)
Using Korn Shell on HP-UX 11.x
Question about signals between two shells. First shell is the parent that kicks off the second shell. The first shell is going to ignore a standard set of signals, but I want the second shell to signal back to its parent if event X happens. Can I do something of... (5 Replies)
Right now I have implemented autossh between ServerA & ServerB which are sun solaris based. I have made this shell script. I am facing one problem which I am going to discuss now.
The problem is when I sftp some files (suppose there is 10 files I have to transfer through sftp) from one server
to... (2 Replies)
Hi folks,
I have tried to add some trap detection in the below script....this script is used to monitor database activities...in a rather awkward way :rolleyes:....
The idea behind adding trap is that....this script creates lots of temporary files in the running folder to store the count... (1 Reply)
Wasn't really sure where to put this, since I'm using C in UNIX, but I am making my own shell... so, what's going on is this:
For our program, we had to create our own shell, and if the user pressed ctrl-c just at the cmdline, then this signal would be ignored, but if there is a foreground... (1 Reply)
I know there is a command called trap which can be used to capture the signals from a shell script and redirect the control to a required function (such as a cleanup).
My question is - Those of you who have written lot of shell scripts - do you always write a set of trap commands to capture... (4 Replies)
Use and complete the template provided. The entire template must be completed. If you don't, your post may be deleted!
1. The problem statement, all variables and given/known data:
That is the last reply I received from my instructor, and I'm looking for some alternatives.
When using... (2 Replies)
I am having issues with trap not working inside a script. I am currently trying this on a Knoppix system V 5.1. What I would like to happen is when I press control c, a message gets echoed and the script is ended. For example:
#! /bin/bash
trap "echo CTRL c was pressed ; break" SIGINT... (11 Replies)
let LIMIT=50
function check {
if ]; then
print LIMIT OK
else
print "LIMIT changed!"
fi
}
trap check DEBUG
print $LIMIT
LIMIT=$((LIMIT + 30))
trap - DEBUG
Can anyone tell me how debugging is accomplished?? (4 Replies)
Discussion started by: Karthick N
4 Replies
LEARN ABOUT HPUX
trap
trap(1) User Commands trap(1)NAME
trap, onintr - shell built-in functions to respond to (hardware) signals
SYNOPSIS
sh
trap [ argument n [n2...]]
csh
onintr [-| label]
ksh
*trap [ arg sig [ sig2...]]
DESCRIPTION
sh
The trap command argument is to be read and executed when the shell receives numeric or symbolic signal(s) (n). (Note: argument is scanned
once when the trap is set and once when the trap is taken.) Trap commands are executed in order of signal number or corresponding symbolic
names. Any attempt to set a trap on a signal that was ignored on entry to the current shell is ineffective. An attempt to trap on signal 11
(memory fault) produces an error. If argument is absent all trap(s) n are reset to their original values. If argument is the null string
this signal is ignored by the shell and by the commands it invokes. If n is 0 the command argument is executed on exit from the shell. The
trap command with no arguments prints a list of commands associated with each signal number.
csh
onintr controls the action of the shell on interrupts. With no arguments, onintr restores the default action of the shell on interrupts.
(The shell terminates shell scripts and returns to the terminal command input level). With the - argument, the shell ignores all inter-
rupts. With a label argument, the shell executes a goto label when an interrupt is received or a child process terminates because it was
interrupted.
ksh
trap uses arg as a command to be read and executed when the shell receives signal(s) sig. (Note that arg is scanned once when the trap is
set and once when the trap is taken.) Each sig can be given as a number or as the name of the signal. trap commands are executed in order
of signal number. Any attempt to set a trap on a signal that was ignored on entry to the current shell is ineffective. If arg is omitted
or is -, then the trap(s) for each sig are reset to their original values. If arg is the null (the empty string, e.g., "" ) string then
this signal is ignored by the shell and by the commands it invokes. If sig is ERR then arg will be executed whenever a command has a non-
zero exit status. If sig is DEBUG then arg will be executed after each command. If sig is 0 or EXIT for a trap set outside any function
then the command arg is executed on exit from the shell. The trap command with no arguments prints a list of commands associated with each
signal number.
On this man page, ksh(1) commands that are preceded by one or two * (asterisks) are treated specially in the following ways:
1. Variable assignment lists preceding the command remain in effect when the command completes.
2. I/O redirections are processed after variable assignments.
3. Errors cause a script that contains them to abort.
4. Words, following a command preceded by ** that are in the format of a variable assignment, are expanded with the same rules as a vari-
able assignment. This means that tilde substitution is performed after the = sign and word splitting and file name generation are not
performed.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWcsu |
+-----------------------------+-----------------------------+
SEE ALSO csh(1), exit(1), ksh(1), sh(1), attributes(5)SunOS 5.10 23 Oct 1994 trap(1)